# Gardener — Managed Kubernetes Service Across Any Infrastructure

> Gardener delivers homogeneous Kubernetes clusters at scale on any infrastructure provider using hosted control planes, automating lifecycle management from creation to upgrades.

## Install

Save in your project root:

# Gardener — Managed Kubernetes Service Across Any Infrastructure

## Quick Use
```bash
# Install gardenctl CLI
curl -LO https://github.com/gardener/gardenctl-v2/releases/latest/download/gardenctl_v2_linux_amd64
chmod +x gardenctl_v2_linux_amd64 && sudo mv gardenctl_v2_linux_amd64 /usr/local/bin/gardenctl
# Target a garden cluster
gardenctl target --garden my-garden
# List shoot clusters
gardenctl get shoots
```

## Introduction
Gardener is an open-source Kubernetes-native system developed by SAP that manages the complete lifecycle of conformant Kubernetes clusters across multiple cloud providers and on-premises infrastructure. It follows the "Kubernetes manages Kubernetes" principle by running workload cluster control planes as pods in a seed cluster.

## What Gardener Does
- Provisions and manages Kubernetes clusters (called Shoots) on AWS, Azure, GCP, OpenStack, and bare metal
- Runs workload cluster control planes as pods in seed clusters (hosted control planes)
- Automates Kubernetes version upgrades, OS updates, and certificate rotation
- Provides built-in monitoring, logging, and alerting stacks per cluster
- Supports hibernation of clusters to reduce costs during off-hours

## Architecture Overview
Gardener uses a three-tier model: the Garden cluster hosts the Gardener API server and manages global state; Seed clusters host the control planes of workload clusters; Shoot clusters are the end-user Kubernetes clusters. Each Shoot's API server, etcd, and controllers run as pods in a Seed, while worker nodes run on the target infrastructure. Extensions allow adding support for new cloud providers, operating systems, and networking plugins.

## Self-Hosting & Configuration
- Deploy the Garden cluster with the Gardener Operator, which manages the Gardener control plane components
- Register Seed clusters that will host Shoot control planes
- Define CloudProfiles describing available machine types, images, and Kubernetes versions per provider
- Create Shoot manifests specifying provider, networking, worker pools, and maintenance windows
- Use the Gardener Dashboard (web UI) for visual cluster management and monitoring

## Key Features
- Hosted control planes reduce per-cluster overhead and improve security isolation
- Cluster hibernation and wake-up for cost optimization in dev/test environments
- Extensible architecture supports adding new infrastructure providers without modifying core code
- Automated credential rotation for kubeconfig, service account tokens, and etcd encryption keys
- Built-in vertical pod autoscaler and cluster autoscaler for workload and infrastructure scaling

## Comparison with Similar Tools
- **Cluster API** — Kubernetes SIG project for cluster lifecycle; Gardener adds hosted control planes and operational automation
- **Rancher** — multi-cluster management UI; Gardener focuses on hosted control planes and provider abstraction
- **EKS/GKE/AKS** — cloud-native managed Kubernetes; Gardener provides a consistent experience across all providers
- **KubeSphere** — multi-cluster platform focused on developer experience and app store
- **Crossplane** — infrastructure provisioning via Kubernetes CRDs; complementary to Gardener's cluster management

## FAQ
**Q: What does "Kubernetes manages Kubernetes" mean in Gardener?**
A: Gardener uses standard Kubernetes primitives (pods, deployments, CRDs) in seed clusters to run and manage the control planes of workload (shoot) clusters.

**Q: Which cloud providers does Gardener support?**
A: AWS, Azure, GCP, OpenStack, Alicloud, and bare metal via provider extensions. Community extensions add support for additional platforms.

**Q: Can I run Gardener on-premises?**
A: Yes. With OpenStack or bare-metal provider extensions, Gardener manages clusters on private infrastructure the same way it manages cloud-based ones.

**Q: How does Gardener handle upgrades?**
A: Gardener automates Kubernetes minor version upgrades and OS patch updates within configured maintenance windows, with rollback capabilities if health checks fail.

## Sources
- https://github.com/gardener/gardener
- https://gardener.cloud/docs/

---
Source: https://tokrepo.com/en/workflows/asset-b6c38b58
Author: AI Open Source